Ladder Siamese Network: a Method and Insights for Multi-level Self-Supervised Learning

Siamese-network-based self-supervised learning (SSL) suffers from slow convergence and instability in training. To alleviate this, we propose a framework to exploit intermediate self-supervisions in each stage of deep nets, called the Ladder Siamese Network. Our self-supervised losses encourage the intermediate layers to be consistent with different data augmentations to single samples, which facilitates training progress and enhances the discriminative ability of the intermediate layers themselves. While some existing work has already utilized multi-level self supervisions in SSL, ours is different in that 1) we reveal its usefulness with non-contrastive Siamese frameworks in both theoretical and empirical viewpoints, and 2) ours improves image-level classification, instance-level detection, and pixel-level segmentation simultaneously. Experiments show that the proposed framework can improve BYOL baselines by 1.0% points in ImageNet linear classification, 1.2% points in COCO detection, and 3.1% points in PASCAL VOC segmentation. In comparison with the state-of-the-art methods, our Ladder-based model achieves competitive and balanced performances in all tested benchmarks without causing large degradation in one

Realizing Community Invigoration and an Inclusive Society through International Human Resources : Findings from an Open Studies Course at Tokushima University

我が国では，グローバル化及び少子高齢化・人口減少が進む中，外国人労働者の積極的な活用が喫緊の課題となっている。但し外国人材の獲得は，国内の地域間だけでなく国際的な競争にもさらされているため，彼らの我が国及び徳島への定着を促し，産業の維持・発展並びに地域活性化と共生を実現していくには，各地域社会において具体的な方策が求められる。こうした問題意識のもと，JICA 四国と徳島大学は2019 年に連携して公開講座を実施した。本稿は，その講座内容を整理し，実施成果より今後の展望を考察するものである。 本稿での考察を産学官民の観点から整理すると，①産業界においては，外国人と日本人の双方にとって生産性の高い労働環境を整備し，国内外でのビジネス展開強化の意識を持つこと，②学術界においては，地域社会及び経済の発展に資する研究成果の社会実装と，グローバルな視野を有し，地域に貢献できる人材の育成・輩出を促進すること，③行政においては，外国人一人ひとりの生活及び労働面等の異なるニーズに寄り添い，柔軟に対応する姿勢を持つとともに，地域全体で外国人の受入れと共生に向けた意識を育むための環境を醸成していくこと，④市民社会においては，外国人を地域に住む仲間として受入れ，彼らと協働しながら誰にとっても住みやすいまちづくりを促進していくこと，が今後の展望として析出された。今後，それぞれの業界が上記課題を具現化し，かつ効果的に連携できる方途を模索しながら，戦略的な地域活性化及び外国人材との共生に向けた前進が期待される

GNSS Array Antenna for Mitigating Multipath Errors in Urban Environment

GNSS signal vulnerability has been a major concern especially for safety-of-life applications such as aircraft operations. Therefore, a GNSS array antenna technology was investigated focusing on beamforming to mitigate multipath errors in urban environment including airport surfaces. A commercial three-element GNSS antenna and RF-Front end were used to obtain digital IF data. The recorded In-phase/Quadrature IF data for three antennas were combined with proper weight to form beams towards satellites after so-called hardware biases were calibrated. Test results in multipath-rich environment demonstrated that 50-70% reduction of pseudorange errors due to multipath were possible if the beamforming algorithms were applied

Rev-erb agonist improves adverse cardiac remodeling and survival in myocardial infarction through an anti-inflammatory mechanism

Rev-erb α, known as nuclear receptor 1D1 (NR1D1), regulates circadian rhythm, modulates glucose and lipid metabolism, and inflammatory response. However, little is known about the effect of Rev-erb agonist on the progression of myocardial infarction (MI) and heart failure. To investigate it, wild-type male mice underwent sham-operation or permanent ligation of the left anterior descending coronary artery to create MI model. Rev-erb agonist SR9009 (100 mg/kg/day) or vehicle was intraperitoneally administered. Echocardiography was performed to evaluate cardiac function 1 week after surgery. The gene and protein expression levels in the left ventricles (LVs) were determined with real-time PCR, western blotting, and immunofluorescence. Moreover, immune cell infiltration into the LVs was analyzed by flow cytometry. Survival rate and reduced LV function were significantly improved by the treatment with SR9009 after MI. The expression level and plasma concentration of brain natriuretic peptide were significantly lower in MI mice treated with SR9009 (MI+SR) than in MI mice treated with vehicle (MI+V). Moreover, the mRNA expression levels of inflammatory-related molecules such as Il6, Mcp1, Ly6g, Cd11b, matrix metallopeptidase (Mmp)9, and the protein expression levels of phosphorylated NF-κB p65, phosphorylated ERK, and phosphorylated p38 were also significantly lower in MI+SR than in MI+V. Immunofluorescence intensity for MMP-9 was enhanced in the LVs, but was less so in MI+SR than in MI+V. Furthermore, infiltrations of neutrophils and proinflammatory macrophages in the LVs were dramatically increased in MI+V and were significantly suppressed in MI+SR. Rev-erb agonist SR9009 treatment inhibited post-MI mortality and improved cardiac function through modulating inflammation and remodeling process

Impacts of conversion of tropical peat swamp forest to oil palm plantation on peat organic chemistry, physical properties and carbon stocks

Ecosystem services provided by tropical peat swamp forests, such as carbon (C) storage and water regulation, are under threat due to encroachment and replacement of these natural forests by drainage-based agriculture, commonly oil palm plantation. This study aims to quantify how the chemical and physical properties of peat change during land conversion to oil palm. This will be addressed by comparing four separate stages of conversion; namely, secondary peat swamp forests, recently deeply drained secondary forests, cleared and recently planted oil palm, and mature oil palm plantation in North Selangor, Malaysia. Results indicate accelerated peat decomposition in surface peats of mature oil palm plantations due to the lowered water table and altered litter inputs associated with this land-use change. Surface organic matter content and peat C stocks at secondary forest sites were higher than at mature oil palm sites (e.g. C stocks were 975 ± 151 and 497 ± 157 Mg ha− 1 at secondary forest and mature oil palm sites, respectively). Land conversion altered peat physical properties such as shear strength, bulk density and porosity, with mirrored changes above and below the water table. Our findings suggest close links between the organic matter and C content and peat physical properties through the entire depth of the peat profile. We have demonstrated that conversion from secondary peat swamp forest to mature oil palm plantation may seriously compromise C storage and, through its impact on peat physical properties, the water holding capacity in these peatlands

土壌中の有機・無機複合体に関する研究(農芸化学部門)

土壌中で有機物は無機成分と複合体を形成して安定に存在している。本研究は土壌中の粒径別有機・無機複合体について, 腐植と無機成分特に粘土との相互作用を解明し, さらに腐植化過程を複合体の腐植について明らかにすることを目的として行なわれた。土壌を粒径別に分画することで複合体中の腐植の組成的な複雑性は減少した。すなわち, 粒径の粗い画分には腐朽度の低い植物遺体が主に存在し, 腐朽が進みもっとも腐植化度の高まった腐植は粗粘土画分に存在した。細粘土画分には, 植物遺体の分解物や微生物遺体等が混入していると推察した。粘土画分の腐植はFe^およびAl^を介して粘土と複合体を形成していることが熱重量分析から推察された。粘土鉱物がモンモリロナイトの場合, 層間に腐植の一部が吸着していることをX線回折から明らかにした。カオリナイトの場合, 腐植は粘土表面のステップと外縁部(エッジ)に吸着していることを電子顕微鏡観察から明らかにした。なお, この場合吸着は偏在しており, 非晶質鉄, アルミニウムの沈積部位に偏りがあると考えられた。次に, 抽出腐植酸を分子量別に分画するための条件を検討し, 高分子腐植酸は球状凝集体を形成し, 低分子腐植酸およびフルボ酸は繊維状凝集体を形成することを電子顕微鏡観察から見い出した。さらに, 種々の粒径の無機成分と結合している腐植酸を抽出後, 分子量別に分画し, その光学的性質, 官能基量, 赤外線吸収スペクトルを測定した結果, 腐植化の進行は植物遺体の腐朽分解によってのみ進むものではなく, 植物遺体が分解され, 分解物が重縮合し, さらに酸化的解裂と酸化的重縮合反応がくり返されることによって腐植化が進行すると推察された。従って腐植化の最終産物は, 黒色調の著しい二重結合の平均的密度の高い官能基量のやや多い重縮合高分子腐植酸であると結論された。In most soils a large proportion of the organic material reacts with the inorganic colloids to form the organo-clay complex. The present work was undertaken to investigate the interaction between humus and the minerals especially clay minerals and the humification process of humic acid in organo-mineral complexes. Four paddy soil samples were used; OK (polder land), TO (Humic allophane soil), LB (Grumusol) and RS (Acid sulphate soil). The soil was saturated with sodium ions, and then sonified in water suspension. After sonification the soil suspension was separated into various size organo-mineral fractions by successive sedimentation and centrifugation; and Fe^, and that the Al^-humus complex would be extracted with alkaline reagent selectively, so Fe^-complex would be remain in non extractable form as humin complex. In case of LB and RS fcx, TG study indicated that the humus in the complexes was in a closer association with clay, as compared to other clay complexes. 3) From the X-ray diffractometric evidence and the results of the glycerol sorption on clays and humus-clay complexs, it was offered that the natural sorption of humic materials occured in the interlamella spaces of montmorillonites in LB fcx and ccx. 4) The gold flash decoration method was applied to observe the surface microtopography of clay-humus complexes with electron microscopy. In case of kaolinite-humic acid complexes, abundant humic acid was observed on crystal edge and the steps on surface of some kaolinite particles. In naturally occurring humus-clay complexes too humic substances were adsorbed on clay in the same manner as above. Surface microtopography of humin complexes had etched marks. These may be due to the effect of alkaline reagent to extract the Al^-humus complex selectively. 5) Gel chromatography has been applied to fractionation or purification of soil humic acid, and gel-solute interactions due to aromaticity and heterocyclic rings of humic acids have been discussed. A suitable gel-solute system for the study of humic acid was looked for. Further, fractionated humic acids were characterized with respect to their buoyant density in sucrose density gradient sedimentation analysis, and their shapes were observed with electron microscopy. Electron micrographs of these fractionated humic acids showed that the diameter of granular aggregates tend to be smaller in the decreasing order of their molecular weight, and fluffy aggregates, which dominate in fulvic acid fraction, increased in the above order. 6) Humic acids were extracted and purified from the organo-mineral complexes described above, and fractionated on the basis of molecular weight differences by gel chromatography with proposed gel-solute system; high molecular weight (ca. 50000) and low molecular weight (ca. 10000-20000) fractions. These molecular weight fractions of humic acids were studied for their optical properties, IR spectra, C/N ratios and functional groups, as determined by colloid titration method. From these studies it was inferred that extinction coefficients of humic acids at 400nm indicated the π electron density, Δ log K values indicated the polymerization degree of aroma

Exercise training reduces ventricular arrhythmias through restoring calcium handling and sympathetic tone in myocardial infarction mice

Exercise can improve morbidity and mortality in heart failure patients; however, the underlying mechanisms remain to be fully investigated. Thus, we investigated the effects of exercise on cardiac function and ventricular arrhythmias in myocardial infarction (MI) induced heart failure mice. Wild‐type male mice underwent sham‐operation or permanent left coronary artery ligation to induce MI. MI mice were divided into a sedentary (MI‐Sed) and two intervention groups: MI‐Ex (underwent 6‐week treadmill exercise training) and MI‐βb (oral bisoprolol treatment (1 mg/kg/d) without exercise). Cardiac function and structure were assessed by echocardiography and histology. Exercise capacity and cardiopulmonary function was accepted as oxygen consumption at peak exercise (peak VO2). Autonomic nervous system function and the incidence of spontaneous ventricular arrhythmia were evaluated via telemetry recording. mRNA and protein expressions in the left ventricle (LV) were investigated by real‐time PCR and Western blotting. There were no differences in survival rate, MI size, cardiac function and structure, while exercise training improved peak VO2. Compared with MI‐Sed, MI‐Ex, and MI‐βb showed decreased sympathetic tone and lower incidence of spontaneous ventricular arrhythmia. By Western blot, the hyperphosphorylation of CaMKII and RyR2 were restored by exercise and β‐blocker treatment. Furthermore, elevated expression of miR‐1 and decreased expression of its target protein PP2A were recovered by exercise and β‐blocker treatment. Continuous intensive exercise training can suppress ventricular arrhythmias in subacute to chronic phase of MI through restoring autonomic imbalance and impaired calcium handling, similarly to that for β‐blockers

デコレーション法による粘土鉱物表面の電子顕微鏡写真(農芸化学部門)

デコレーション法を適用して, 粘土鉱物表面の微細構造を観察した。用いた粘土鉱物は, 結晶度の異なる5種類のカオリナイトである。結晶度の高い指宿カオリン, 関白カオリンでは, 表面にあまりステップは見られず, エッジの近くに集中してカオリンの外形と平行に多くのステップが見られる。次に結晶度のよいジョージアカオリンでは, 表面全体にステップが多く見られ, ほとんどすべてが, 面対称性に律せられている。結晶度の悪い瀬戸蛙目および木節粘土の表面には, 規則性を持たず, 小さくまとまったステップが散在し, 面対称性に律せられていないものも多い。又, 指宿, 関白, ジョージアカオリンでは, 結晶軸の方向の異なった二つの結晶が食いちがってつながった形をとるものが, ごくまれに見られた。粘土鉱物の表面微細構造を観察するには, デコレーション法は有効な手段であり, 結晶成長を類推する一つの方法となりうると考えられる。Electron microscopy-decoration method evolved for ion crystals was applied to observation of clay minerals. Five sorts of kaolinite crystallized in different stages were used. In case of highly crystallized Ibusuki- and Kanpaku kaolinite, many growth steps, in parallel with crystal edge, were found in the reagion near the crystal edge. Many pseudohexagonal growth pattern were observed on the surface of well crystallized Georgia kaolinite. In low crystallized Seto-Kibushi- and Seto-Gaerome clay (kaolinite), small irregular shaped steps were found on the surface. Curious crystal just look as two crystals stuck in mutually was observed, rarely, for Ibusuki, Kanpaku and Georgia kaolinite